1. Field of the Invention
The present invention relates to an image forming device such as a copy machine, a facsimile machine and a printer, and an image forming method.
2. Description of the Related Art
In a conventional laser printer known as an image forming device, when an electrostatic latent image is formed on a photoconductive body by using 100% light energy even on an inner part of a black solid part of the image, a large amount of toner adheres to the photoconductive body. Not only is the toner consumed in a large amount, but there is also a drawback of deterioration in the quality of the image recorded on paper, such as trailing of the toner. In consideration of such a drawback, by using a matrix of pixels, depending on whether surrounding pixels are white or black, a determination can be made as to whether a target pixel is located at a peripheral part or at an inner part of the black solid part. An exposing energy for pixels located in the black solid part is reduced in order to reduce an amount of toner adhered to the photoconductive body. This technology is generally known as “Toner Saving”.
In the above-described technology, by using the matrix of pixels consisting of the target pixel and the surrounding pixels, depending on whether the surrounding pixels are white or black, a determination can be made as to whether or not to reduce the light energy of the target pixel. In fact, a value of the surrounding pixels is arranged in one piece of data and this piece of data is input to a memory as an address. The exposing energy is reduced in accordance with this piece of data output from the memory. That is, the toner is saved for the target pixel.
However, since it becomes necessary to provide a memory, the scale of the circuitry increases. In particular, to improve accuracy for determining whether the target pixel is located at the peripheral part or at the inner part of the black solid part, the size of the matrix increases and a greater capacity of the memory becomes necessary. Meanwhile, when image data becomes multilevel, the number of bits of data as the address increases and a greater capacity of memory becomes necessary.